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Fencer Intel
low 3.3

CVE-2021-31815 json

GAEN (aka Google/Apple Exposure Notifications) through 2021-04-27 on Android allows attackers to obtain sensitive information, such as a us…

published 5y ago modified 4mo ago also EUVD-2021-18691

cvss
3.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

GAEN (aka Google/Apple Exposure Notifications) through 2021-04-27 on Android allows attackers to obtain sensitive information, such as a user's location history, in-person social graph, and (sometimes) COVID-19 infection status, because Rolling Proximity Identifiers and MAC addresses are written to the Android system log, and many Android devices have applications (preinstalled by the hardware manufacturer or network operator) that read system log data and send it to third parties. NOTE: a news outlet (The Markup) states that they received a vendor response indicating that fix deployment "began several weeks ago and will be complete in the coming days."

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Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • themarkup.org https://themarkup.org/privacy/2021/04/27/google-promised-its-contact-tracing-app-was-completely-private-but-it-wasnt referenced PoC, tagged "exploit" by a source, unverified
  • blog.appcensus.io https://blog.appcensus.io/2021/04/27/why-google-should-stop-logging-contact-tracing-data/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-319 Cleartext Transmission of Sensitive Information

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.